Infrared spectra of the ammonium ion in crystals. Part XIII. Crystal structure of (NH4)2[AlF5(H2O)] and NH3D+ probe-ion spectra in (NH4)2[AlF5(H2O)], NH4AlF4, and (NH4)3ZnCl5, with remarks on structural filiation of AMF4 fluorides

1985 ◽  
Vol 63 (2) ◽  
pp. 516-525 ◽  
Author(s):  
Osvald Knop ◽  
T. Stanley Cameron ◽  
S. P. Deraniyagala ◽  
D. Adhikesavalu ◽  
Michael Falk
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Infrared Spectra ◽  
The Other ◽  
Ammonium Ion ◽  
Colour Space ◽  
Low Frequencies ◽  
Space Groups ◽  
Disordered Phase ◽  
Normal Formula

The crystal structure of (NH4)2AlF5•H2O = (NH4)2[AlF5(H2O)] (Pbcn, a = 10.192(4) Å, b = 8.037(2) Å, c = 7.844(1) Å, Z = 4) consists of isolated [AlF5(H2O)]2− octahedral and NH4+ ions. The octahedra are linked by [Formula: see text] bonds to form zigzag chains parallel to c and the chains are cross-linked by normal [Formula: see text] hydrogen bonds to the NH4+ ions. The ir characteristics of the hydrogen bonds in this and the other two title compounds were probed with the NH3D+ ion between 10 and 293 K. The probe-ion spectra confirm the C1 symmetry of the ammonium ion in (NH4)2[AlF5(H2O)] and point to [Formula: see text] bonding of moderate strength. For NH4AlF4 the spectra agree with the expectation from the known crystal structure of both the ordered and the disordered phase, but the transition at ~150 K is not evident in the evolution of the spectra with temperature. Detailed assignment of the ND stretching and bending component absorptions of NH3D+ is not possible for (NH4)3ZnCl5 = (NH4)3(ZnCl4)Cl. However, the unusually low frequencies of two of the components of the ND stretching absorptions in this crystal indicate the existence of [Formula: see text] bonds stronger than those in NH4Cl. The filiation of the known AMF4 structures deriving from TlAlF4 is presented in terms of two-colour space groups.

The effect of partial methylation of the glycine amino group on crystal structure inN,N-dimethylglycine and its hemihydrate

2012 ◽  
Vol 68 (8) ◽  
pp. o283-o287 ◽  
Author(s):  
Vasily S. Minkov ◽  
Elena V. Boldyreva
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Water Molecules ◽  
Amino Group ◽  
Asymmetric Unit ◽  
Partial Methylation ◽  
Space Groups ◽  
Carboxylate Groups ◽  
Anhydrous Compound ◽  
Additional Hydrogen

N,N-Dimethylglycine, C4H9NO2, and its hemihydrate, C4H9NO2·0.5H2O, are discussed in order to follow the effect of the methylation of the glycine amino group (and thus its ability to form several hydrogen bonds) on crystal structure, in particular on the possibility of the formation of hydrogen-bonded `head-to-tail' chains, which are typical for the crystal structures of amino acids and essential for considering amino acid crystals as mimics of peptide chains. Both compounds crystallize in centrosymmetric space groups (PbcaandC2/c, respectively) and have twoN,N-dimethylglycine zwitterions in the asymmetric unit. In the anhydrous compound, there are no head-to-tail chains but the zwitterions formR44(20) ring motifs, which are not bonded to each other by any hydrogen bonds. In contrast, in the crystal structure ofN,N-dimethylglycinium hemihydrate, the zwitterions are linked to each other by N—H...O hydrogen bonds into infiniteC22(10) head-to-tail chains, while the water molecules outside the chains provide additional hydrogen bonds to the carboxylate groups.

Infrared spectra of the ammonium ion in crystals. Part VIII. Spectroscopic criteria of highly-bent hydrogen bonds

1980 ◽  
Vol 58 (9) ◽  
pp. 867-874 ◽  
Author(s):  
Osvald Knop ◽  
Wolfgang J. Westerhaus ◽  
Michael Falk
Keyword(s):  
Low Temperature ◽  
Hydrogen Bonds ◽  
Infrared Spectra ◽  
Room Temperature ◽  
Ammonium Ion ◽  
Temperature Transition ◽  
Increasing Temperature

Available evidence suggests that (1) the stretching frequencies of highly-bent hydrogen bonds decrease with increasing temperature, regardless of whether the bonds are static or dynamic in character, to a single acceptor or to several competing acceptors; and (2) departures from symmetric trifurcation (or bifurcation) toward asymmetric situations lower the stretching frequency. In further support of these criteria isotopic probe ion spectra between 10 K and room temperature have been obtained for taurine and for trigonal (NH4)2MF6 (M = Si, Ge, Sn, Ti). Evidence of a low-temperature transition at 100(10) K in trigonal (NH4)2SnF6 is presented, and existence of the previously reported transition at 38.6 K in trigonal (NH4)2SiF6 is confirmed. Symmetry changes associated with these transitions are discussed.

scholarly journals Crystal structure of the co-crystalline adduct 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane (TATD)–4-bromophenol (1/2)

2015 ◽  
Vol 71 (5) ◽  
pp. 463-465 ◽  
Author(s):  
Augusto Rivera ◽  
Juan Manuel Uribe ◽  
Jicli José Rojas ◽  
Jaime Ríos-Motta ◽  
Michael Bolte
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Hydrogen Bonds ◽  
Rotation Axis ◽  
The Other ◽  
Two Dimensional ◽  
Asymmetric Unit ◽  
Species Association ◽  
Crystalline Adduct ◽  
Aminal Cage

The structure of the 1:2 co-crystalline adduct C8H16N4·2C6H5BrO, (I), from the solid-state reaction of 1,3,6,8-tetraazatricyclo[4.4.1.13,8]dodecane (TATD) and 4-bromophenol, has been determined. The asymmetric unit of the title co-crystalline adduct comprises a half molecule of aminal cage polyamine plus a 4-bromophenol molecule. A twofold rotation axis generates the other half of the adduct. The primary inter-species association in the title compound is through two intermolecular O—H...N hydrogen bonds. In the crystal, the adducts are linked by weak non-conventional C—H...O and C—H...Br hydrogen bonds, giving a two-dimensional supramolecular structure parallel to thebcplane.

scholarly journals Crystal structure of dimanganese(II) zinc bis[orthophosphate(V)] monohydrate

2015 ◽  
Vol 71 (2) ◽  
pp. 154-156 ◽  
Author(s):  
Ghaleb Alhakmi ◽  
Abderrazzak Assani ◽  
Mohamed Saadi ◽  
Lahcen El Ammari
Keyword(s):  
Crystal Structure ◽  
Transition Metal ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
The Other ◽  
Water Molecules ◽  
Framework Structure ◽  
Hydrothermal Conditions ◽  
Metal Phosphates

The title compound, Mn2Zn(PO4)2·H2O, was obtained under hydrothermal conditions. The structure is isotypic with other transition metal phosphates of the typeM3−xM′x(PO4)2·H2O, but shows no statistical disorder of the three metallic sites. The principal building units are distorted [MnO6] and [MnO5(H2O)] octahedra, a distorted [ZnO5] square pyramid and two regular PO4tetrahedra. The connection of the polyhedra leads to a framework structure. Two types of layers parallel to (-101) can be distinguished in this framework. One layer contains [Zn2O8] dimers linked to PO4tetrahedraviacommon edges. The other layer is more corrugated and contains [Mn2O8(H2O)2] dimers and [MnO6] octahedra linked together by common edges. The PO4tetrahedra link the two types of layers into a framework structure with channels parallel to [101]. The H atoms of the water molecules point into the channels and form O—H...O hydrogen bonds (one of which is bifurcated) with framework O atoms across the channels.

scholarly journals Crystal structure ofN-carbamothioyl-2-methylbenzamide

2015 ◽  
Vol 71 (6) ◽  
pp. o425-o425 ◽  
Author(s):  
Farook Adam ◽  
Nadiah Ameram ◽  
Wai Mun Tan
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Aromatic Ring ◽  
Dihedral Angle ◽  
Title Compound ◽  
The Other ◽  
Asymmetric Unit ◽  
Compound C

There are two molecules in the asymmetric unit of the title compound, C9H10N2OS. In one, the dihedral angle between the aromatic ring and the carbamothioyl group is 52.31 (7)° and in the other it is 36.16 (6)°. Each molecule features an intramolecular N—H...O hydrogen bond, which generates anS(6) ring and the O and S atoms have anantidisposition. In the crystal, molecules are linked by N—H...S and N—H...O hydrogen bonds, generating separate [130] and [1-30] infinite chains. Weak C—H...O and C—H...S interactions are also observed.

Dependence of the Distortion of the Square Pyramids in N, N-Dimethylethylenediammonium Pentachloroantimonate(III) on the Geometry of Hydrogen Bonds

2001 ◽  
Vol 56 (6) ◽  
pp. 521-525 ◽  
Author(s):  
Maciej Bujak ◽  
Jacek Zaleski
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Intermolecular Interactions ◽  
Mean Value ◽  
The Other ◽  
Monoclinic System ◽  
Bond Lengths ◽  
Pyramidal Geometry ◽  
The Mean ◽  
Square Pyramidal Geometry

AbstractN ,N-Dimethylethylenediammonium pentachloroantimonate(III) crystallizes in the monoclinic system, in space group P21/c (a = 12.460(2), b = 10.252(2), c = 10.330(2) Å, β = 97.75(3)°, V = 1307.5(4) Å3, Z = 4, dc = 1.997, dm = 1.99(2) g/cm3). The crystal structure of [(CH3)2NH(CH2)2NH3][SbCl5] consists of isolated [SbCl5]2- anions and [(CH3)2NH(CH2)2NH3]2+ cations. The [SbCl5]2- anion has a distorted square pyramidal geometry, presenting one short axial and four long equatorial Sb-Cl bonds. The square pyramids are characteristically stacked one close to the other, parallel to the c axis. The voids between the anionic sublattice are filled by [(CH3)2NH(CH2)2NH3]2+ cations. The five non-equivalent Sb-Cl bond distances within the [SbCl5]2- square pyramid are significantly different. The equatorial Sb-Cl bonds are in the range 2.427(2)-2.968(2) Å, whereas the axial one is 2.384(1) Å long. The study reveals that N-H...C1 hydrogen bonds are responsible for the deformation of equatorial Sb-Cl bonds from the mean value of 2.654(7) Å. Analysis of intermolecular interactions between the [SbCl5]2- pyramids in the structure, reflected in changes of Sb-Cl bond lengths from the values characteristic of non-interacting pyramids, leads to the conclusion that the van der Waals radius of Sb is significantly smaller than that estimated by Pauling.

scholarly journals Crystal structure of ammonium 3′-azido-3′-deoxythymidine-5′-aminocarbonylphosphonate hemihydrate: an anti-HIV agent

2014 ◽  
Vol 70 (11) ◽  
pp. 396-399
Author(s):  
Maxim V. Jasko ◽  
Galina V. Gurskaya ◽  
Marina K. Kukhanova ◽  
Ivan S. Bushmarinov
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Water Molecule ◽  
Rotation Axis ◽  
Three Dimensional ◽  
Amide Group ◽  
The Other ◽  
Asymmetric Unit ◽  
Anti Hiv

The asymmetric unit of the title compound, NH4+·C11H14N6O7P−·0.5H2O, contains one 3′-azido-3′-deoxythymidine-5′aminocarbonylphosphonate (ACP–AZT) anion, half of an NH4+cation lying on a twofold rotation axis and in another position, occupied with equal probabilities of 0.5, an NH4+cation and a water molecule. The amide group of the ACP–AZT anion is disordered (occupancy ratio 0.5:0.5), with one part forming an N—H...O (involving C=O...H4N+) hydrogen bond and the other an O—H...N (involving C—NH2...OH2) hydrogen bond with the components of the split NH4+/H2O position. The pseudorotation parameters of ACP–AZT set it apart from previously studied AZT and thymidine. In the crystal, the various components are linked by N—H...O, O—H...O, N—H...N, C—H...O and C—H...N hydrogen bonds, forming a three-dimensional framework.

scholarly journals Crystal structure of 2,4,6-trimethylbenzoic anhydride

2017 ◽  
Vol 73 (11) ◽  
pp. 1735-1738
Author(s):  
Michael A. Land ◽  
Katherine N. Robertson ◽  
Jason A. C. Clyburne
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
The Other ◽  
Asymmetric Unit ◽  
Aromatic Rings ◽  
Rotation Symmetry ◽  
Compound C ◽  
Benzoic Anhydride ◽  
Ether Solution

The title compound, C20H22O3, was formed in the reaction between 2,4,6-trimethylbenzoic acid andN,N-diisopropylethylamine in the presence of 1,3-dichloro-1,3-bis(dimethylamino)propenium hydrogen dichloride, and was recrystallized from diethyl ether solution. It is the first exclusively alkyl-substituted benzoic anhydride to have been structurally characterized. The asymmetric unit consists of a half molecule, the other half of which is generated by twofold rotation symmetry; the dihedral angle between the symmetry-related aromatic rings is 54.97 (3)°. The geometric parameters of the aromatic ring are typical of those for 2,4,6-trimethylphenyl substituted groups. The C=O and C—O bond lengths are 1.1934 (12) and 1.3958 (11) Å, respectively, and the angle between these three atoms (O=C—O) is 121.24 (9)°. In the crystal, molecules are linked by weak C—H...O hydrogen bonds and C—H...π interactions. The packing features wavy chains that extend parallel to [001].

scholarly journals Crystal structure of 5-(1-benzofuran-2-yl)-3-(4-methylphenyl)-4,5-dihydro-1,2-oxazol-5-ol

2015 ◽  
Vol 71 (7) ◽  
pp. o492-o493
Author(s):  
A. J. Ravi ◽  
A. C. Vinayaka ◽  
S. Jeyaseelan ◽  
M. P. Sadashiva ◽  
H. C. Devarajegowda
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Three Dimensional ◽  
Ring System ◽  
The Other ◽  
Dihedral Angles ◽  
Compound C ◽  
Dimensional Network ◽  
The Mean

In the title compound, C18H15NO3, the isoxazole moiety adopts a shallow envelope conformation, with the C atom bearing the OH group displaced by 0.148 (1) Å from the mean plane through the other four atoms. The mean plane of this ring (all atoms) subtends dihedral angles of 87.19 (6) and 15.51 (7)° with the benzofuran ring system (r.m.s. deviation = 0.007 Å) and the 4-methylphenyl ring, respectively. In the crystal, molecules are linked by O—H...N hydrogen bonds, generating [001]C(5) chains, with adjacent molecules in the chain related byc-glide symmetry. Weak C—H...O interactions link the chains into a three-dimensional network.

scholarly journals Crystal structure ofmeso-3,3′-(1,4-phenylene)bis(2-phenyl-2,3,5,6-tetrahydro-4H-1,3-thiazin-4-one)

2018 ◽  
Vol 74 (10) ◽  
pp. 1497-1499
Author(s):  
Hemant P. Yennawar ◽  
Quentin J. Moyer ◽  
Lee J. Silverberg
Keyword(s):  
Crystal Structure ◽  
Carbon Atom ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Phenyl Ring ◽  
Hydrophobic Interactions ◽  
The Other ◽  
Asymmetric Unit ◽  
Phenyl Rings ◽  
Thiazine Ring

The crystal structure of the title compound –meso-C26H24N2O2S2with two stereocenters – has half the molecule in the asymmetric unit with the other half generated by a crystallographic center of inversion. The thiazine ring is in a conformation that is between half-chair and envelope [θ = 52.51 (17)°]. The phenyl ring on the 2-carbon atom of the thiazine ring is pseudo-axial. The central phenyl ring of the molecule is close to orthogonal to the phenyl rings on either side with an angle of 76.85 (11)° between those planes. In the crystal, pairwise, weak C—H...O hydrogen bonds between the central phenyl ring and the oxygen atoms of neighboring molecules result in continuous strips propagating along thea-axis direction. Hydrophobic interactions of the C—H...π type are also observed.

Sign in / Sign up

Export Citation Format

Share Document